Original article: Incorporations of blueberry extracts into soybean‐protein‐isolate film preserve qualities of packaged lard

The effect of blueberry‐extract incorporation into soybean‐protein‐isolate edible film on the quality of packaged lard was compared with vitamin E or butylated hydroxyl anisole (BHA) incorporations individually during the storage at 36 °C and relative humidity of 40% for 5 weeks. Blueberry‐extract incorporations into soybean‐protein‐isolate film showed a greater tensile strength, lower water vapour permeability and lower oxygen permeability than vitamin E or BHA incorporations individually. On the other hand, the antioxidant capacity of soybean‐protein‐isolate film incorporated with the blueberry extract was greater than that incorporated with vitamin E and similar to that incorporated with BHA. Moreover, soybean‐protein‐isolate film incorporated with the blueberry extract showed a greater capacity to delay the lard hydrolysis than that incorporated with BHA, and a similar capacity to that incorporated with vitamin E. Consequently, blueberry‐extract incorporations into soybean‐protein‐isolate film not only improved mechanical and barrier properties, but also delayed the oxidation and hydrolysis of packaged lard. Therefore, blueberry‐extract incorporations into soybean‐protein‐isolate films have potential as a packaging material which will preserve the qualities of stored lard.     

Cholesterol photosensitised oxidation of horse meat slices stored under different packaging films

The effect of the type of packaging film (transparent vs. light-protecting red film) was evaluated on the formation of cholesterol oxidation products (COPs) in refrigerated horse meat slices stored in retail conditions under light exposure for 8 h. In meat wrapped with a transparent film, COPs increased from 233 (control) to 317 μg/g of fat, whereas the red film delayed cholesterol oxidation and offered protection against COPs formation, since COPs decreased from 173 (control) to 139 μg/g of fat after 8 h of light exposure. In addition, light opened the epoxy ring and led to the formation of triol, which was actually absent at T_0. A proper packaging film may represent a useful strategy to retard oxidative degradation in a light-sensitive, high pigment- and fat-containing food, such as horse meat.     

The effect of hydrogen crossover on open-circuit voltage in polymer electrolyte membrane fuel cells

Even though the measured open-circuit voltage in a H₂-O₂ PEM fuel cell is invariably about 200-250 mV lower than that predicted from thermodynamics (1.229 V at 25 °C), there is no unequivocal explanation of this phenomenon available in the literature, although several hypotheses exist. Based on a theoretical model of mixed potential with a priori parameters, it is shown here that this voltage loss under open-circuit conditions can be attributed exclusively to hydrogen crossover and the resulting oxygen reduction reaction overpotential at the cathode. The analytical model predictions agree well with available experimental results.     

Effect of addition of Agaricus blazei mushroom residue to milk enriched with Omega‐3 on the prevention of lipid oxidation and bioavailability of bioactive compounds after in vitro gastrointestinal digestion

The residue from a hydroalcoholic extract of the mushroom Agaricus blazei (MAR) was evaluated for phenolic compounds, flavonoids and antioxidant activity. The ability of MAR to slow the oxidation of Omega‐3 resulting from light exposure in milk matrix, and its bioavailability after in vitro digestion was investigated. MAR presented phenolic compounds and flavonoids and showed antioxidant activity. At each concentration, addition of MAR to Omega‐3‐supplemented milk inhibited the production of conjugated dienes and malonaldehyde compared with samples without MAR. The bioavailability assay showed that polyphenols were still present after in vitro digestion and had antioxidant activity.     

Utilisation possibility of Enterococcus faecalis isolates from neonate's faeces for production of fermented sausages as starter cultures

This study aimed at assessing the utilisation possibility of Enterococcus faecalis as starter cultures for production of fermented sausages. The E. faecalis isolates isolated from faeces samples of 5‐day‐old healthy newborn babies, identified by 16SrDNA sequencing and free from virulence determinants as proven by genomic sequencing, were used for fermented sausages production as starter culture. Six treatments (four inoculated with four different E. faecalis isolates, one with commercial starter culture and one control) were prepared. The inoculation with E. faecalis showed a stronger acidification compared with the control. The treatments with E. faecalis showed significantly higher flavour and acceptability scores in comparison with the control or commercial starter culture. Both of commercial starter culture and E. faecalis were positive with tyramine. Apart from the amine production, the inoculation with E. faecalis generally improved the acidifying activity and flavour of the products, suggesting their application potentials in fermented sausages production as starter cultures.     

Effect of raspberry pomace extracts isolated by high pressure extraction on the quality and shelf‐life of beef burgers

Raspberry pomace extracts isolated with supercritical carbon dioxide (SCE) and pressurised ethanol/water (ETE) were tested in beef burgers. Only ETE additives effectively inhibited lipid oxidation and the growth of microorganisms, as it was observed by measuring the changes of thiobarbituric acid reactive substances, bacterial counts and the content of O₂ and CO₂ during storage in the modified atmosphere package. ETE additives also demonstrated some meat colour preservation effects, which were assessed by the intensity of hamburger colour and metmyoglobin concentration. However, ETE additives did not alter burger's taste at the applied concentrations (up to 1%). It may be concluded that the most effective extracts possessing strong antioxidant and antimicrobial activity may be isolated from raspberry pomace by the pressurised liquid extraction with a hydroethanolic solvent; such extracts may be considered as promising additives in meat products for improving their stability and enriching with beneficial to health phytochemicals.     

KNS烟草烤炉专用钢的研发试制

玉溪新兴钢铁有限公司研发了一种KNS烟草烤炉专用钢,对钢的化学成分、铸坯低倍组织、钢的力学性能、金相显微组织、夹杂物、晶界铜偏析、耐硫酸腐蚀性及高温抗氧化性等进行研究分析。结果表明:钢中添加了Ni、Cr、Cu、Sb等多种微合金耐蚀元素,化学成分均匀,铸坯低倍缺陷级别≤1.0级,低倍组织缺陷少且尺寸小,有利于轧材性能的改善;钢的抗拉强度为460~520 MPa,断后伸长率≥32%,铁素体晶粒度≥10.0级,非金属夹杂物≤1.0级;晶界、晶内铜含量基本一致,在晶界处没有出现铜偏析现象,避免了轧制过程"铜脆"裂纹的发生;耐硫酸腐蚀率为4.6 mm/a,800℃高温氧化跌落损失率为0.57%,具有良好的耐硫酸腐蚀性及抗高温氧化性。     

Lessons from metal oxides to find why Nature selected manganese and calcium for water oxidation

The problem of finding a way to store energy from abundant sources such as sunlight, wind or geothermal heat is critical. Water splitting toward hydrogen production is a very promising way for the goal. Although the cathodic reaction is of major interest in hydrogen production, the concurrent anodic water oxidation, which provides cheap electrons for the cathodic reaction, is a limitation for hydrogen formation. The best water-oxidizing catalyst was found by Nature million years ago and used in plants, algae and cyanobacteria. We believe learning from the natural system is very promising, because Nature has been successfully splitting water for millions of years, using an inexpensive and environmentally friendly MnCa oxido cluster. Herein we study the phenol oxidation by some nano-sized metal oxides in the presence of H₂O₂. As metal oxides are functional and structural models for the water-oxidizing complex in Photosystem II, the results can be expanded for the natural site. We suggest that low organic compound oxidation under water oxidation is an important issue to select manganese and calcium ions for water oxidation.     

Mass Transfer Reaction Kinetics of β‐Isophorone Oxidation by Air in an Agitator Bubbling Reactor

The mass transfer reaction kinetics of β‐isophorone (β‐IP) oxidation reaction by air was investigated in a lab‐scale agitator bubbling reactor. This reaction can be regarded as instantaneous and there exists a critical concentration of β‐IP. When the catalyst concentration is kept unchanged, the reaction rate is only controlled by the gas film and the reaction kinetics is of zero order with respect to β‐IP when the β‐IP concentration lies over the critical concentration. The reaction rate is controlled by the dual film and the kinetics is of first order with respect to β‐IP when its concentration is below the critical concentration. Under the gas film‐controlling condition, the effect of temperature, agitator speed, and aeration on the reaction rate is evaluated. A correlation equation of gas phase volumetric mass transfer coefficients combining superficial gas velocity and agitator speed is defined.